Heating system



y M. ELLIS HEATING -SYSTEM Filed Aprii 25.

' w L9 La 1921 2 Shank-Sheet; 1

finder Feb. 2 9 L. M. ELLIS HQEATING SYSTITJM 2 Sheets-Sheet 2 FiledApril 25. 1921 F f. A v .T m A wfi Q Patented Feb. 22 ,'1"9 27.

UNITED STATES P ATENT OFFICE.

LEWIS M. ELLIS, or CHICAGO, ILLINOIS, ASSIGNOR TO TUBAL BOILER co.-, orCHICAGO,

ILLINOIS, A CORPORATION or ILLINOIS.

ima'rmo SYSTEM.

Applicationflled Apri1 25, 1921'. Serial No. 434,381, I q,

The present invention relates to heating systems, and is an improvementupon. the heating system disclosed in my prior Patent No. 1,399,052,issued December 6, 1921.

In this patent I have disclosed a system of heating having particularapplication to ovens, kilns and other heating "devices in which it isrequired .to maintain relatively high temperatures, ranging in the neighborhood of between O degrees F. to- 800 degrees F. These ovens or kilnshave illustration in enameling ovens and the like. This heating systemis characterized by the use of a superheated vapor or gas which ismechanically circulated through the system at a sufliciently high speedto eliminate any tendency to condense in the oven co1l or other heatradiating device. The vapor'or gas is preferably, thouglr notessentially steam, and when employing this. medlum the system includes asuperheater for adding heat to the steam, the oven, kiln or otherheating device; and a pump, compressor, or the like which functions asan 1mpell1ng de-' vice for moving the steam through -the cir cuit. Aboiler or other source of steam or vapor is employed formaking up thelosses incurred in running and for supplylng the initial body of fluidmedium. The theory 0 of mechanically circulating the superheated steamat a relatively rapid ,rate through the oven coil is to prevent thetemperature of the steam from dropping below the saturation point in theoven coil, and preferably throughout the circuit, and to increase theheating efficiency of the coil by clrculatmg the, heat conducting mediumtherethrough at a relatively highspeed.

One of the principal objects of the invention'is to increase theefl'iciency of the circulating pump or blower by so disposing 1t in thesystem that it handles a relatively smaller or minimum volume of steamand at a point in the cycle where this steam 1s of relatively lowtemperature. The reduced volume of steam permits of a smallercirculating device with a roportionate reduction in heat absorption ythe circulating de vice, and the lower temperature of the steam avoidsoverheating of the-device and other mechanical difficulties.

A further object of v the invention is to provide control meansresponsive to the temperature in the oven, or'in the oven 0011,

for controlling. the rate of circulation through the system, or forrendering inefi'ectl Ve the circulating device so as to interruptcirculation at a predetermined temperature. Afurther object isto providemeans for venting the circuit into a region of considerably lowerpressure at predetermined times n the operation of the-system, such asfor tlji e purpose-of accelerating the rate of flow o purpose ofbringing the oven temperature u to its desired value, or for morequickly imtiatin'g the operation of the system.

A-further and invention isv to provide means which will function as anelastic reservoir for releasing heat and pressure from thecircuit-during periods when the oven is absorbingless than the normal ormaximum amount of heat. During thesperiods the temperature of thesuperheated steam must be maintained at substantially the same point asduring the normal or high working conditions of'the oven, but vowing tothe fact that a smaller quantity of heat is being absorbed in the oven,a large percentage of the original superheat given to the steam at thesuperheate'r is returned to the boiler point of the'circuit. Here thissuperheat is largely absorbed in the steam through the oven coil for theprominent object of the v the boiler, with the result that increasedgeneration of steam follows. Where a very large percentage of theoriginal superheat is returned from the oven, sufficient, when added tothe external firing of the boiler, to. generate an excessive quantity ofsteam in the boiler. The result is tion I contemplate an efficient andeconomi-' this heat may be I thatthe steam pressure in the circuit'tendsto rise to an undesirable point, either from the stand-point of safety,or .from. the fact cal method of compensating or absorbing thesefluctuations in temperature and pressure by associating with theboiler'or circuit either'a steam engine, a heating appa-v ratus, or anysecondary heat absorbing means, and by regulating the external firing ofthe boiler either manually orautomati- 1 cally to controlthe externalheat input to the boiler in accordance withthe pressure in the system.According tothis method,

the boiler is externally fired to supply a sub- .sta'nti'allyconstantsteam pressure of the de- "sired degree suitable for the ovencircuit and for the secondary heat absorbing means. When the quantity ofsuperheat imparted to .the steam in the oven clrcuit is in excess of theoven requirements the excess superheat heats the boiler internally andof itself or with the assistance of the external firingthis internalheat tends to develop an excessive steam pressure. At this point,however, the

external firing of the boiler is cut down either by the attendant at theboiler or by automatic means. Owing to the forced circulation of thesteam in the circuit'andthe high degree of superheat imparted thereto,the heat returned to the boiler from the This secondary'heat absorbingmeans is provided by the steam engine, steam heating apparatus, or othermeans, drawing steam from' theboiler point of the circuit. The relativecapacities of the boiler and of the secondary heat absorbing means arepref erably such as to insure that "the secondary heat absorbing meanswill withdraw steam from the boiler at a rate equal to or greater thanthe highest possible rate of steam generation caused by the returnedsuperheat from the oven, so that the secondary heat absorbin means isalways capable o'f'utilizing all 0% the returned supcrheat in order toavoid the generation of the excessive pressures in the system. From theforegoing it will be seen that the boiler, the secondary heat absorbingmeans, and the regulated firing of the boiler thus constitute an elasticthermal reservoir for withdrawing heat and pressure from the circuitduring low Working periods of the oven. Thus the-system is made capableof meeting widely varying demands, but at the'same time, maximum heateconomy is retained. The above fea ture of my invention may have thefurther aspect of efficiently-utilizing the exhaust steam of lowertemperature which is discharged from the oven coil' by secondary heatabsorbing means having particular aptitude for this character of steam,as I shall hereinafter describe.

The foregoing objects will more clearly appear in the accompanyingdescription of a preferred embodiment of my invention.

In the drawings illustrating this embodiment: 1

Figure liis a diagrammatic layout of one form of my improved system, and

' Figure 2 is a Si i1 r view of another form of the system employingthermal controls for regulating the circulation through'the fullydescribed 1.. the above mentioned patent, a boiler 4, which may be ofany suitable "type and capacity capable of generating the requiredpressure and volume of steam, supplies steam which is either saturated,or of a relatively low super-heat. The steam is discharged from thisboiler through a pipe 6 which extends to the intake of a circulatingdevice 7. This chculating device may be of the reciprocating higherpressure than that atthe steam. The superheater illustrated is 7provided with a suitable burner, although it is to be understood thatany controllable source of heat may be employed. The burner is providedwith a regulating valve 11 which controls the amount of fuel burnedunder the superheater.- The rate of heat delivery to the superheater 10is controlled heat transferring medium as it passes into the hot end of.the oven or kiln 5. For this purpose, I have provided a temperatureresponsive element 12 for regulating the fuel controlvzilve 11. Thetemperature responsire element 12, instead of being subjected merely tothe temperature of the steam delivercd, may be subjected to thetemperature of the kiln, or to the temperature of the exhaust steamdischarged from the oven in accordance with the temperature of the coil.From the temperature responsive element 12 the highly superheated steamflows through pipe 13 into the-end of a heat radiating coil 14 in theoven 5. The coil 14 may be in the form of a single sinuated coil asillustrated, or it may consist of-a plurality of coils connected in:parallel between inlet and outlet headers. From the discharge end of,the coil 14 the steam is conducted back to the boiler 4 by way of pipe.15.

Any suitable secondary heat absorbing meansmay' be connected to theboiler or to the circuit for cooperating the boiler in providing anelastic thermal reservoir or excess heat absorbing means. At 16 I haveshown an ordinary steam engine which may be run either constantly orintermittently,

upon the return of excess heat to the boiler, this, engine serving todrive any suitable of, pipe 17,41 suitable valve 17 being in powerapparatus. The boiler isconnected tol this secondary heat absorbingmeans by way of the superheater would require a'large'.

furnace for the boiler 4 may be either manual or automatic, both beincontemplated responsive element. 18' in the ipe line 17 or at any otherpoint-in the system preferably adjacent the boiler, and having thispressure responsive element control a fuel valve 19 and thereby regulatethe external -firing of the boiler.

In the operation of the system, the blower 7' circulates the steamthrough the oven coil 14 so fast that the drop in tempera" ture of thesteam by contact with the sides of the tube 14 does not reduce thetemperature of the steam tothe point of saturation. 'l'hus, the drop intemperature of the steam 'is controlled by the speed of movement of thesteam and it is possible to hold the mmperature of the coil veryclosely'to a predetermined figure with only asmall thermal drop, andconsequently with an even distribution of heat throughout the coil. Theoven temperatures which it is possible to obtain by this high speedcirculation of superheatedsteam' are far in excess of those ordinarilypossible with saturated. steam. For example, oven temperatures of from500 degrees F. to 600 degrees I11 canbe maintained throughout the ovenor'kiin, with pressures "in the neighborhood of 100 or 150 pounds..l/Vith saturated steam these temperatures would involve prohibitivepressures. j

It will be noted that the blower 7 handles only the saturated steampassing from the boiler 4 to the superheater-'10. This saturated steamhas least volume and confequently the'blower 7 can be of smaller sizewith proportionately less heat loss by conduction through the walls ofthe blower..

Owing to the high superheat which must be imparted to the steam in thesuperheater 10 the expansion of the steam is relatively large, and thehandling of this expanded, high temperature steam on the outlet sideblower and involve unnecessary heat loss, even where the blower isdisposed at the dis- 0 charge end of the heating coil 14. More'- over.the lowertemperatures of the saturated steam between the boiler 4 andthe superheater 10 avoid large thermal losses,

overheated bearings, and other mechanicaldisadvantages incident tothefiow of a very,

high temperature gas through a 'blowcr.

The superheatreturned from' the oven to the boiler point of the-circuithas the tendency to generate steam in the boiler,in quantities dependingupon the amount of superheat and the balance or adjustment of thesystem. ,VVere provision not made for taking care ofthis returnedsuperheat the generation pf steam therefrom might at times developundesirable pressures in the described.

system. Any such increase in pressure would not influence the controlelement 12 as .thiselement is only responsive to temperatures. Accordingto the present method, where the firing of the boiler is man uallycontrolled the attendant upon noting any such increase in pressure cutsdown on the external firing. It is assumed that during this time theengine or other heat absorbing means is continuously withdrawing heatfrom the boiler. The excess heat may thus be drawn directly to theengine or indirectly in the form of steam vaporized in the boiler. Theultimate fact is that the engine requires a continuous supply of heatand when the oven circuit is operating normally a certain percentage ofthis heat is supplied an excessive percentage of superheat-is returnedfrom the oven this heat is w1thdr'awn the furnace under the boiler, butwhen from the oven circuit and is fed to the 011- gine, the furnace heatunder the boiler being reduced commensurately with the quantity of heatsupplied from the oven circuit. \Vhere the firing of the boiler iscontrolled automatically the generation of pressure in the system beyonda predeterminedpoint' operates automatically to reduce the rate offiring of the boiler. This shifts the thermal balance so that some, ormore, of the excess heat from the oven is used in supplyingthe secondaryheat absorbing means and less is supplied from the boiler furnace. Itwill be obvious that the system may have any desired thermal adjustmentor balance. For example, a certain percentage of the heat returned fromthe oven may be supplied to the engine in the form of excess heat evenwhen the oven is absorbing a relatively large amount of heat; or, thesystem may be so balanced that it is only when the oven is absorbing butlittle heat that the return heat therefrom is utilized to run theengine.

In the arrangement illustrated in Figure 2, saturated steam is suppliedfrom a boiler 4 through -pipe 6 to the blower 7 ,the blower H in thisinstance being shunted by a by-pass 20 designed to control thecirculation through the system From the"dis charge.

outlet of the blower 7 the steam is con ducted through pipe 9 tothesuperheater pipe 13 to the oven coil 14, which may be arranged in eitherof the forms-previously The temperature of the discharged steam iscontrolled by the usual temperature responsive element 12 which operatesthrough the valve 11 to govern. the

rate of fuel supply to the burner of-the superheater'lO. For venting thecoil 14 to atmosphere or to a region of lower pressure, the dischargeend of the coil has an outlet opening 21 controlled by an automaticvalve 3- 22. To permit-fof'manual venting of the I coil a. secondaryoutlet 23 is provided, controlled by a manually operated valve 24. Thetwo outlets 21' and 23 may discharge -to atmosphere,-or may vent into aheating system of lower pressure or any other region of sufliclently lowpressure to insure a highly accelerated flow of steam through the coil14. In the normal operatlon of the system,

the steam is discharged from the coil lfl: into the usual discharge pipewhich com municates with a steam main 25 extending I from the boiler 4to the engine 16. A check valve 26 is'interposed in the pipe 15 toprevent the steam from backing up mtothe coil '1 14 during non-operatingintervals of the oven.

. .ture of the oven above a predetermined mmi- V mum, the element 36 hasconnection 30 with a valve operating device 31 which controls theautomaticcva-lve 22.

The same general theory of operatlonpreviously described ischaracteristic vof this system. However, when thetemperature in t e oven5 reaches a predetermined maximum, the temperature element 36 respondsby openingthe valve 29 through the instrumentality conn'e I circula ofthe valve operating device 28 and 'ction 27 The result is that theforced "tion of the steam through the system is interrupted by a thesteam recirculating through the by-pass 20, and consequently the oven isgiven an opportunity to cool off,

' whereupon the valve 29 closes and. the circu lationvthrough the ovencoil is resumed as -11,.tl'1e temperature responsive element 36 before.*It will be noted that such steam as is circulated throughtthe oven coilis maintained at a substantially constant-temperature by thethermostatic control 12 and valve and valve'29 controlling the existenceof a circulation through the oven coil or the vol ume When the oventemperature recedes to a preof steamcirculated therethrough.

determined minimum, the temperature responsive element .36 operates. toopen the valve 22 through the instrum tality of the valve operatingdevice 31, thereby causing.

A'gage 3-1 indicates to the fireman or engia rapid discharge of steamfrom the discharge end oi the oven coil with a conse- Y quent. increaseof steam flow through the tomatically closing Whenthe desired 'temovencoil. in augmentation of that created by theblower 7. This results ina'rapid rise (pf-temperature in the oven, the valve 22 au perature isrestored. This increased rate oi circulation through. the oven coil foraccentu'ated heating of theoven or. for quicklybringing the ove n up toheat may be obtained at any time by the opening-of the manually operatedvalve 24. The maximum restoration of the desired oven temperature.

The relatively cooler steam from the discharge end of the oven 0011 maybe circulated back intothe boiler through the steam .rnain 25; or itmaybe mixed with saturated steam drawn from the boiler 'through thesteam main 25 for the operation of the engine 16; or this dischargesteam from the oven coil maybe utilized for the running of the engine tothe exclusion of the saturated l steam from the boiler 4 by the closingof the valve 32 and opening the valve 17". That is to say, by closingthe valve 32 and open ing the valve 17 in the pipe line 25, the entire'volume of steam discharged from the oven coils may be utilized foroperating the engine 16. Of course, it would not be practical to "dothis except during low'worki'ng periods of theheat radiating'coils. Theengine 16 in reality constitutes an independent secondary heat;absorbing means associated with the heating system on the outlet side ofthe heat radiating coils for utilizing only heat in the vapor dischargedfrom the coils in excess of that required for maintainingapredeterminedpressure in the system. The

engine 16 should, in order to attain the best results in the operationof the system, only be interposed in the'return line of the system whena thermal outlet is needed, or in other Words, when the coils are notfunctioning at their full capacity. The present "invention, however,should not be limitedto the specific type of secondary m'ea'ns employed,nor to the manner ii -Which it.is specifica'lly associated withthesystem, but the invention should only be limited in so far is defined bypended claims.

the scope and spirit of-theap- I In this embodiment I have assumed the'firin'g of the boiler as being manually. controlled, although anautomatic control such" described .may be employed:

as previously neer the pressure in the system. By control ling theexternal firing of the boiler 4 the attendant can make the boiler andengine. function as a thermal reservoir oroheat absorbi ng'means inprecisely thesame manner as before'detcribed. When the 'ovenis returninga relatively large quantity of heat the boiler is fired at aproportionately lower rate. By closing the valve 32 the circulatinaction can be interrupted and the entire v ume of steam from the ovencan be cliverted into the engine 16.

In the present. form, the boiler 4 and superheater are illustrated asbeinglocated in proximity so that the flue gases from the superheater 10can be conducted through an exhaust flue 33 into the further release ofheat from the gases to the Water in the boiler. The thermally responsiveelement 36 maybe provided with any suit-ablegauge or indicating dial 36'for indicating externally in the oven 5.

I claim: 1. In a heating system, the combinat on in a vapor circuit,said circuit comprising a boiler, a superheater for superheating the thetemperature existing vapor to a temperature above the temperaturecorresponding to the saturated vapor at the pressure prevailing in thesystem, a

radiator in said circuit for receiving the superheated vapor, andimpelling means interposed in said circuit between said boiler and saidtion with vapor.

2; In a heating system,

the relatively low temperature a vapor circuit comprising a'boiler, asuperheater, a heat radiating coil, anda pump, said superheater heatingthe vapor to a temperature above the temperature corresponding to thesaturated vapor at the pressure prevailing in the system, said heatradiating coil giving off heat from the vapor and reducing thetemperature of the same to a point above the corresponding temperatureof saturated vapor, said pump moving the vapor away from the radiatingcoil before the temperature of the vapor drops below the saturathepressure prevailing in the circuit, said pump being interposed in saidcircuit between said boiler and said superheater, whereby said pumphandles the low temperature steam of minimum volume passingbetween saidboiler and said superheater.

3. In combination, vapor generating means, a-vapor superheater, a heatradiator connected thereto, a vapor impelling meansfor driving the vaporthrough said superheater r and said heat radiator, and means controlledby conditions at said heat radiator for automatically by-passing sa-idvapor impelling means. a

4. In aheating system, vapor generating I means, a vapor superl1eater,.a heat radiator connected thereto, a vapor pump for drivingthe vapor through said superheater and .said heat radiator, a by-passaround said' 7 v vapor-pump,'and

thermally controlled means for automatically controll ng said" by-pass.5. In a heating system, the combination of a vapor circuit, vapor.generating means,

said circuit including a heater for superboiler 4; for a still radiatingcoil.

superheater for creating vcirculaheating the vapor, and -a heatradiating device for receiving the superheated vapor, means forcirculating the vapor through said circuit, and means for venting saidcircuit to a region of lower pressure for accelerating the fiow of vaporthrough said heat radiating device.

6. In a heating system, a vapor generator, a vapor superheater vand aheat radiator connected together in a circuit, a vapor pump for drivingthe vapor through said circuit, and means for venting said circuit-toaccelerate the flow of vapor through said heat radiator. g r

7. In a heating system comprising a vapor circuit, vapor heater in saidcircuit, a heat radiating coil in said circuit for receiving thesuperheated vapor, a vapor vapor, and thermally controlled means forautomatically venting said circuit to accelerate the tlow of vaporthrough said heat 8. In aheating system, the combination of vaporgenerating means, avapor circuit, a vapor superheater in said circuit,an enpump for circulating the closure having a heating coil thereinineluded; in said vapor circuit, a vapor pump tor driving the vaporthrough said circuit, and thermally controlled means responsive to thetemperature in said enclosure for automatically venting the circuit onthe outlet side of said heating coil for accelerating the flow of vaporthrough said coil.

9. In a heating system, the combination of a vapor circuit, vaporgenerating means, a heater in said circuit for superheatingthe vapor toa temperature above the temperature corresponding to the saturated vaporat the pressure prevailing in .the system, an enclosure comprising acoil in said circuit for giving ott heat from the vapor and reducing thetemperature of the vapor to a point above the corresponding temperatureof saturated vapor at the same pressure, a blower in said circuit fordriving the vapor through said heater and said coil, a

y-pass shunting said blower, a vent in said the vapor in the systemincluding an inlet, and impelling means for circulating the vapor inthesystem interposed intermediate the outlet of the vapor generator and theinlet of the superheating means.

' including an outlet, means for superheating "11. In a heating system,aboiler for generating vapor, a superheater forsuperheating the vapor,and a pump for causing the vapor to be. circulated interposed betweenthe mediate an outlet of the boiler and an inletboiler and the nerator,said pump handling only the ow temperature vapor of mimmum'volume'passing between said boiler and said superheater.

12. In a heating system, a boiler for generating vapor, a superheaterfor superheating the. vapor, radiating means disposedintermediate anoutlet of the'said superheaterand an inlet 6f, the boiler for receivingthe vapor, and impelling means disposed interof the superheater forcirculating the vapor through the system.

13. In a heating system, vapor generating means, -.means forsuperheating the vapor,-

., radiating means for receiving the superheated vapor, means forcausmgthe vapor termined point to accelerate the flow'of the -for takingheat therefrom, means for caus-. ing the steam to flow through the saidra-v superheated vapor through the radiating means;

, 14. In a heating system, a source of steam radiating means forreceiving the steam and diati'ng' means, and thermally controlle meansassociated with the radiating means for automatically ventin the systemwhen 'the temperature within t e radiatingmeans drops below apredetermined point to accelerate the flow of the steam through the ra-1 diating means.

15. In a -heating' system, means -for gencrating vapor, means forsuperheating the vapor, heat radiating means for receiving thesuperheated vapor, means for causing the vapor to be circulated throughthe system, and thermal means associated with the heat radiating meansfor venting the sys-'. tem when the temperature of the said heatradiating means falls below a predetermined amount and for by-passingthe vapor around the-circulating means toretard the flow of the' vaporbefore it reaches the heat radiating means when the temperature ;of saidheat radiating means exceeds a predetermined point. v

16. In a heating system, a source {of steam,

heat radiating means for. receiving the steam, means for causing the.steam to flow through the said heat radiating means, and

thermal means associated with the heat-rm diating means for venting thesystem when the temperature of the said heat radiating means falls belowa predetermined amount and for by-passing the steam around thesaidsecond mentioned means toretard the flow of 'the vapor in the systemwhen the temperature of the said heat radiating means exceedsgiven'amount.\

17 In a heating system, a'source asecond means controlled by theconditions at the said heat radiator for automatically Icy-passing thesteam around the first means to retard the flow of the steam inthesystem.

In witness whereof, I hereunto subscribe my name this 13th day of April,1921.

LEWISMQELLIS,

v of steam, aheat radiator, a first means for causing the steam toflowthrough the heat radiator, and

